Technical description and composition of the DEXP F50B8000H TV, type of panel and applicable modules. The composition of the modules.DEXP LED
Model: F50B8000H
Chassis / Version: RSAG7.820.5872
Panel: HE500HFD-B52 S9 GM
LED backlight: HE500HF-B57 RSAG7.820.5815, LT-1134017-A
T-CON: T500HVN08.3 50T20-C06
LED driver (backlight): integrated into PSU
PWM LED driver: LX27901
MOSFET LED driver: 5N50
Power Supply (PSU): RSAG7.820.5687 / ROH HLL-4855WA
PWM Power: CP1271, NCP1608
MOSFET Power: 10N60, 8N65
MainBoard: RSAG7.820.5872 / ROH
IC MainBoard: EEPROM: 24C64, SPI Flash: 25Q64, NAND Flash: H27U4G8F2DTR
Tuner: RE221ZN
Technical Specifications F50B8000H
DEXP F50B8000H
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The DEXP F50B8000H does not turn on at all. The control lights do not light or flash. The TV on the remote control and the control panel buttons do not respond.
Typically, with such manifestations, the defect is caused by faulty elements in the main power supply module RSAG7.820.5687. It is then necessary to measure its output voltages and, if they are absent, you should check the power switches (10N60, 8N65) and the rectifier diodes of the converters for a short circuit probability.
In case of breakdowns of diodes in the secondary circuits, the converter can operate in emergency short circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor at the source of the key usually breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) CP1271, NCP1608, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
The most likely in these cases is a malfunction of the LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the RSAG7.820.5872 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - EEPROM: 24C64, SPI Flash: 25Q64, NAND Flash: H27U4G8F2DTR and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
If there is no reception of television channels, but the TV is working properly from external devices, first of all, check the voltage of the tuner RE221ZN and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
For F50B8000H TV owners, we recommend that you contact qualified personnel with the necessary work experience for repairs! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> RSAG7.820.5687 Power supply
The appearance of the MainBoard RSAG7.820.5872 is shown in the figure below:RSAG7.820.5872
The appearance of the power supply
Main features of the DEXP F50B8000H device:
Installed matrix (LED panel) HE500HFD-B52 S9 GM.
The matrix control uses the Timing Controller (T-CON) T500HVN08.3.
To power the backlight LEDs, a converter is used, combined with the power supply, controlled by the LX27901 PWM controller. As power elements of the LED driver, keys of the 5N50 type are used.
The necessary supply voltages for all nodes of the DEXP F50B8000H TV are generated by the RSAG7.820.5687 power module or its analogs using CP1271, NCP1608 microcircuits and power switches of the type 10N60, 8N65.
MainBoard - the main board (motherboard) is an RSAG7.820.5872 module, using EEPROM chips: 24C64, SPI Flash: 25Q64, NAND Flash: H27U4G8F2DTR and others.
The RE221ZN tuner provides television reception and channel tuning.
TV DEXP F50B8000H with LCD, diagonal size 50 "(127 cm) in 16: 9 format. The required brightness of the screen is 300 cd / m² LED backlight LED. Contrast - the ratio of maximum brightness to minimum is 3000: 1. In this model The panel with the end position of the backlight LEDs is used - Edge LED.
There is support for 3D images with active (shutter) technology for separating the right and left channels. TV features include watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphical decomposition standard 1080p (Full HD).
The F50B8000H is equipped with SMART software, embedded applications and the ability to work on the Internet. Connecting to the Internet can be done via Wi-Fi. The input high-frequency or video signal is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
The power of the acoustic system of sound 20 W (2x10 W) provide two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, component, VGA, HDMI x4, USB x3, Ethernet (RJ-45), Wi-Fi. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with a support 1150x680x230 mm,.
TV mass: 16.5 kg.
Attention! The DEXP F50B8000H LED TV panel is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.
